Lubricant manufacture



Patented Aug. 14, 1945 tunmclwr MANUFACTURE Ralph E. Darley, Glen Burnie, Mil, aaslgnor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 5, 1942, Serial No. 467.988

4 Claims. (Cl. 252-35) This invention relates to lubricant manufacture and more especially to a novel process for manul'acturing aluminum soap lubricating greases and to the resulting products.

Aluminum greases have heretofore been made chiefly by dissolving or dispersing. an aluminum soap such as aluminum stearate or aluminum naphthenate in a suitable lubricating oil base stock with heat, and, in the case of stearate soap, with subsequent setting to permit conversion of the mixture from a rubbery form to a grease having the desired gel structure, but that method is inconvenient, expensive and is not always attended with satisfactory results in regard to quality and uniformity of the product. It is one object of the present invention to provide a method of manufacturing aluminum greases which will be more economical and simpler or more fool-proof in obtaining a product of satisfactory and uniform quality.

Broadly, the invention comprises reacting hydrous aluminum hydroxide with a saponifiable material such as a fatty acid or naphthenic acid in the presence of mineral lubricating oil base stock, with or without the addition of more oil later, if desired.

The aluminum hydroxide to be used, should contain at least 75%, preferably about 80% to 95%, of water in a substantially homogenous form. In other words, the aluminum hydroxide used should not be a mixture of pure or anhydrous aluminum hydroxide with a mere addition of non-homogeneously admixed water but it should contain at least the indicated minimum amount of water in a more or less combined state. There are several such products on the market which are suitable, some being termed "gelatinous aluminum hydroxide" (which generally contains about 4.5% to 5.0% of aluminum and about 90% to 95% of water) and others being called alumina hydrate pulp, or alumina paste slurry, or gelatinous alumina (which generally contain about 8% of aluminum and about 80% to 85% of water). If desired, more water may be mixed with either of these types of products, but it is especially desirable in the case of the aluminum paste slurry to incorporate a sufficient amount of water to impart a gel-like consistency to the aluminum hydroxide. type of gelatinous alumina available on the market, manufactured by the Aluminum Ore Company, and which may be utilized for the purposes of this invention, has the following identifying characteristics:

Aluminum hydroxide equivalent percent 15-16 Total soda as NarO do 0.1-0.3 sulfates as 803 ..do 0.01-0.02 Organic matter"; Nil Water Balance pH 9-11 Specific gravity 1.04-1.06 Weight/cu. ft lbs- -66 This same product is also available in a substantially neutral form, the soda having ber'i neutralized by sulfuric acid, so that the final product contains about 0.3 to 0.5% sulfates as S03, and has a, pH of about 7.0-7.5.

The saponifiable material to be saponifled by the aluminum hydroxide may be any of those used in making aluminum greases. Stearic acid is suitable as well as other higher fatty acids, such as those obtained from various natural fats and oils, such as cottonseed oil acids. hydrogenated flsh oil acids and naphthenic acids, especially those obtained from petroleum fractions such as kerosene, gas oil or higher fractions, as well as synthetically manufactured acids such as those made by the oxidation of parafl'ln wax. Although the invention is especially applicable to the saponiflcation of acids, fats, e. g., tallow, etc., ma also be saponified although somewhat higher temperatures are required. Mixtures of various types of acids'or other saponiilable material may be used.

- The mineral oil to be used as the lubricating oil base stock should preferably have a viscosity between the approximate limits of 40 to seconds Saybolt Universal at 210 F., and may be obtained from any of the various commonly used crudes such as naphthenic, parafilnic, mixed base crudes, etc., and they may have been refined by various known methods such as distillation, clay treating, acid treating, solvent extraction, etc.

In carrying out the invention, it is preferred to use an amount of hydrous aluminum hydroxide which will substantially neutralize or substantially completely saponif the fatty or naphthenic acids used. It is desirable to carry out the saponification in the presence of an amount of lubricating oil base stock at least equal tothe weight of acids used and preferably in the presence of an amount of oil equal to about 1 to 3 times the weight 01' the acids used. After the saponification, has been completed by stirring and heating the mixture to the desired reaction temperature, i. e., about 200' F., and preferably at about 212 to 220 F., the mixture is then further. heated. to about 200 to 400' F, preferably at about 210 to 300' F., to drive oil. at least a major from a kerosene fraction oi petroleum and had proportion of the free water originally present the following characteristics: in the hydrous aluminum hydroxide as well as Free acid calculated as 018m most of the water formed by the saponiflcation reaction. The amount or water left in the fln- 325; "percent" g-gg ished aluminum grease should be less than about Robinson c 01 or 0.10%, and preferably less than 0.05%. The soap Unsaponmable gaga 4 3 content of the finished aluminum grease may saponmcauon "a l; 235370 vary over a fairly wide range depending upon the water aza intended use of the product, but ordinarily will range between the approximate limits 1.5 to 25%, The gelatinous aluminum hydroxide used c npreferably to about 2 to 24% by weight. After talned about 4.9% aluminum or about 9.27% the original saponiflcation in the presence of A1208 nd 3% water. The aluminum paste part of the oil and subsequent heating to drive slurry contained about 7.5% of aluminum or or! the water. the balance of the lubricating oil 14-20% 2 and a t .80% 0! water. Usubase stock to be used is added with heating and ally 10 p rts y weight of water was added to stirring until the product is homogeneous. every 10 parts by weight of aluminum p te slurry It should be understood, of course, that other n r r to convert the paste into a mass havin a optional addition agents in the art of grease maksuitable gelatinous consistency. The aluminum ing may be used such as adhesivity agents or Paste Slurry contained 7.5% of aluminum per thickeners, such as polyisobutylene having a mo- A120: in about 80% of water.

lecular weight above 1,000, especially above 30,000, These ten tests were all made in steam jacketed oxidation inhibitors such as di-isobutyl phenol, kettles eq ipp wi h me h nic l paddle a tators. etc., as well as dyes, lubricity agents, etc, In most instances, as in Test No. 5, th original The invention may be carried out either by mixture of acid and the small amount of oil was batch operation or continuously, as by continuted to bout 150 F. for V2 hour or an hour ously mixing and heating the saponmable acid and then after addition of the aluminum hydroxwith the hydrous aluminum hydroxide and a me, the temperature was increased to about 260 small amount of lubricating on base Stock and F. or thereabouts and maintained there for about continuously discharging into a drum kept um 4 hours until the contents were cooked substander vacuum or by spraying a film upon a heated In all of the above tests, part of the oil was revolving surfacethe dehydrated mammal being mixed with the acid and aluminum hydroxide removed y scrapersduring saponification, and the balance of oil was Without intending to 1mm? the invention to the added later with thorough heating and mixing. specific i r d e ts and proportions used, the The consistency test and the penetration, both unrollowing experimental data are given to 111115 worked and worked, are the standard A. S. T. M. trate the p ep t f aluminum rea both in tests, the penetration tests being made at 77 F. small laboratory and larger plant batches. In After saponification, Tests 1 to 4 and 6 to 10 did these tests Oil A was an oil having a viscosity f 40 not require any special treatment to obtain and about seconds Saybolt at 210 F. and obtained stabilize the desired gel-like structure, but Test from a naphthenic crude, whereas Oil B was a 5 did; this was done by passing it through chillers i ilar oil of '70 seconds viscosity, and Oil C was to obtain the gel structure.

Table Test No.

LBS. OF MATERIALS USED Acid:

Naphthenic l. l. 76 l. 75 1. 75 225 235 168 168 163 Stearic 75 Al hydrox.:

Gelatinous 4. 00 2. 16 2- 04 P 1. 3i 1 41 390 230 Per eent soap (calod.) 4. s4 14. 79 8.71 4. 21 7. 0o S. I. L. consistency 60 556 600 56 A. 8. T. M. penetration:

Unwnrkad 3 Worked. 84

1 Oil present during saponidemon a. to 3.50 3.50 s. 50 a. 50 458 480 356 335 343 an oil having a viscosity of about 200 seconds Say Both the live laboratory batches (Tests Nos.

bolt at 210 F. and derived from a naphthenic 1-5) and the five plant scale batches (Tests Nos. crude. The naphthenic acid used was obtained 6-10) resulted in aluminum soap greases of satisfactory quality. In general, their texture was smooth and homogeneous; Tests 1 and 10, exclusive of Test 5, were very clear, stringy and had stable consistencies. Test 5 was clear, stable in consistency and by desire had a buttery structure with stringiness. The product of Test 5, to which a small amount of polyisobutylene was added, showed substantially more stringiness or tackiness than the other compositions.

These tests show that surprisingly good results have been obtained in manufacturing an aluminum soap grease from hydrous aluminum hydroxide, whereas heretofore such greases had generally been made by dissolving an already-formed aluminum soap in a lubricating oil, and, on the other hand, anhydrous aluminum hydroxide cannot be used satisfactorily for making aluminum soap greases.

It is not intended that this invention be limited to the specific materials and proportions given for the sake of illustration but only by the appended claims in which it is intended to claim all novelty inherent in the invention as well as all modifications coming within the scope and spirit of the invention.

I claim:

1. The method of manufacturing an aluminum soap grease which comprises saponifying a saponifiable material with gelatinous hydrous aluminum hydroxide containing enough water to give it a gel-like consistency in the presence of at least an amount of lubricating oil equal to the volume of the saponiflabl material.

2. The process of manufacturing an aluminum soap lubricating grease which comprises saponifying an acid selected from the group consisting of naphthenic acids and higher fatty acids with gelatinous hydrous aluminum hydroxide containing at least 75% of water in combined form in the presence of an amount of lubricating oil at least equal to the weight of the acid used, and heating the saponiflcation mixture until substantially all the water has been driven off.

3. The process of manufacturing aluminum soap grease which comprises mixing together a saponifiable organic acid selected from the group consisting of naphthenic acids and higher fatty acids, an amount of lubricating oil at least equal to the weight of said acids, and an amount of gelatinous hydrous aluminum hydroxide containing about 4% to 5% of aluminum and containing about 90% of water, suflicient substantially completely to saponify the acid, heating the resultin mixture to about 200 to 400 F. until saponification has been completed and until substantially all water has been evaporated.

4. The process of manufacturing an aluminum soap lubricating grease which comprises mixing a saponiflable acid selected from the class consisting of naphthenic acids and higher fatty acids with an amount of lubricating oil equal to about 1 to 3 times the weight of acid, stirring and heating said mixture substantially completely to dissolve said acid in said oil, adding to the resulting mixture an amount of hydrous gelatinous aluminum hydroxide containing at least of water in combined form suflicient substantially completely to saponify said acid, stirring and heating the mixture to a temperature of about 210 to 300 F. until saponification has been completed and substantially all water has been evaporated, adding with stirring and continued heating a further amount of lubricating oil to produce a composition having the desired final proportions of soap and oil, and cooling the resulting aluminum soap lubricating grease.

. RALPH E. DARLEY. 

